1. Technical Field
The present invention relates to a pattern formation method.
2. Related Art
In a liquid crystal display device, liquid crystals are sealed between an element substrate and an opposing substrate via a seal member. Orientation films for orienting the liquid crystal are formed on the surfaces of the element substrate and the opposing substrate that are adjacent to the liquid crystal. The orientation films are formed on substantially the entire surfaces of the element substrate and the opposing substrate, and an inkjet method is included as one method for forming the orientation films. In the inkjet method, droplets discharged on a substrate are allowed to coalesce with each other to form an orientation film pattern on the substrate. However, the droplets discharged on the substrate sometimes do not spread uniformly on the substrate. For example, the droplets contract and form stripes, droplets are attracted by other droplets and form bulges, and other problems occur, and a uniform orientation film is difficult to form.
Therefore, a method has been proposed for suitably arranging the droplets discharged from a droplet discharge device so that unfilled parts do not occur in a range that is surrounded by a bank (barrier) (see, Japanese Laid-Open Patent Application Publication No. 2004-31077). In this publication, droplets of a luminescent thin-film material are discharged from an inkjet nozzle two at a time at a discharge interval of two seconds or less into regions that are partitioned by barriers on a pixel electrode formed on a glass substrate, the droplets are dried, and a luminescent thin-film layer is formed. The droplet discharge interval is set to two seconds or less, whereby droplets are attracted by previously discharged and dried droplets, and lack of spreading of the droplets within the banks is prevented as a result. However, the technique disclosed in this publication cannot be applied to a case in which droplets are uniformly spread in a wide range.
Therefore, a method has been proposed for discharging a plurality of droplets from a droplet discharge device and arranging the droplets in the ranges surrounded by the banks without allowing unfilled portions to occur (Japanese Laid-Open Patent Application Publication No. 2006-178208). In this publication, droplets are discharged near the corner parts in the corner parts of the banks in the portions surrounded by the banks, the interval between discharged droplets is reduced towards the center of the portions surrounded by the banks, and droplets are discharged in the center portion near the center. The height of the droplets when the discharged droplets are adjacent to the banks is thereby made substantially uniform in all locations, liquid is prevented from leaking from the banks, and the droplets are uniformly arranged in the portions surrounded by the banks.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved pattern formation method. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.